Electric drive unit

ABSTRACT

An electric drive unit having a multi-phase electric motor and an inverter with a plurality of power semiconductors, an inverter mount, and a plurality of busbars. The power semiconductors are mounted to the base of the inverter mount in an annular arrangement and with the terminals of the power semiconductors extending through the base. Each of the busbars has a first busbar portion, which includes a first body and a set of first fingers that are fixedly coupled to the first body, and a second busbar portion that includes a second body and a set of second fingers that are fixedly coupled to the second body. Associated fingers in the first and second sets of fingers of each bus bar are mechanically and electrically coupled to opposite sides of a corresponding one of the terminals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a bypass continuation of International PatentApplication No. PCT/US2022/019900 filed Mar. 11, 2022, which claims thebenefit of U.S. Provisional Application No. 63/161,164 filed Mar. 15,2021 and U.S. Provisional Patent Application No. 63/209,588 filed Jun.11, 2021. Each of the disclosures of the above-mentioned patentapplications is incorporated by reference as if fully set forth indetail herein.

FIELD

The present disclosure relates to an electric drive unit.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

While there is increasing interest in the electrification of vehicledrivelines, there are significant issues that must be overcome beforevehicles with electrified drivelines substantially displace vehicledrivelines that are powered solely by internal combustion engines. Someof these issues include the cost of the electrified driveline, thevolume of the electrified driveline and its ability to be packaged intoavailable space within a vehicle, as well as the robustness of theelectronics that are employed to operate and control the electrifieddriveline.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In one form, the present disclosure provides an electric drive unit thatincludes a multi-phase electric motor and an inverter. The multi-phaseelectric motor has a stator, which includes a stator core and aplurality of field windings, and a rotor. Each of the field windings isassociated with a corresponding phase of electrical power. The rotor isrotatable relative to the stator about a motor axis. The inverter has aplurality of power semiconductors, an inverter mount, and a plurality ofbusbars. Each of the power semiconductors has a plurality of terminals.The inverter mount has a base. The power semiconductors are mounted tothe base of the inverter mount such that the terminals extend throughthe base and the power semiconductors are arranged in an annular manner.Each of the busbars has a first busbar portion and a second busbarportion. The first busbar portion has a first body and a set of firstfingers that are fixedly coupled to the first body. The second busbarportion has a second body and a set of second fingers that are fixedlycoupled to the second body. Each of the fingers in the set of firstfingers and a corresponding one of the fingers in the set of secondfingers of each of the busbars is mechanically and electrically coupledto opposite sides of a corresponding one of the terminals of the powersemiconductors. The busbars include a positive busbar, a ground busbar,and a plurality of phase busbars. Each of the phase busbars ismechanically and electrically coupled to an associated one of the fieldwindings.

In another form, the present disclosure provides an electric drive unitthat includes a housing assembly, a motor, a transmission, a firstoutput shaft and a bearing. The housing assembly defines a first outputshaft bore and a sump. The motor and the transmission are received inthe housing assembly and the transmission is driven by the motor. Thefirst output shaft is driven by the transmission and extends through thefirst output shaft bore. The bearing is received in the first outputshaft bore and supports the first output shaft for rotation relative tothe housing assembly about an axis. A lubricant supply gallery is formedthrough the housing and intersects the first output shaft bore. Thefirst output shaft bore is tapered in a direction along the axis topromote draining of lubricant in the first output shaft bore to thesump.

In yet another form, the present disclosure provides an electric driveunit that includes a housing assembly, a motor, a transmission, a firstoutput shaft and an inverter. The housing assembly defines a capacitorcavity and a first output shaft bore. The motor is received in thehousing assembly. The transmission received in the housing assembly andis driven by the motor. The first output shaft is driven by thetransmission and extends through the output shaft bore. The inverter ishoused in the housing assembly and is electrically coupled to the motor.The inverter includes a field capacitor that is received in thecapacitor cavity. The housing assembly includes a heat sink that isdisposed in the capacitor cavity. The heat sink is configured to receiveheat that is rejected from the field capacitor.

In still another form, the present disclosure provides an electric driveunit that includes a housing assembly, a motor, a bearing holder and amotor output shaft bearing. The housing assembly has a motor housing,which defines a motor cavity, and a motor housing cover that is coupledto the motor housing to close an open end of the motor cavity. The motoris received in the motor cavity and includes a stator and a rotor. Therotor includes a motor output shaft. The bearing holder is fixedlycoupled to the motor housing cover and is disposed about an axial end ofthe motor output shaft. The motor output shaft bearing is engaged to thebearing holder and the motor output shaft.

In another form, the present disclosure provides an electric drive unitthat includes a housing assembly, an electric motor, a transmission, adifferential assembly, a differential bearing, a differential bearingcover, a spacer and an output shaft. The housing assembly has a motorhousing, which defines a motor cavity, a gearbox and a gearbox cover.The gearbox is coupled to the motor housing, while the gearbox cover iscoupled to the gearbox. The gearbox and the gearbox cover cooperate toform a gearbox cavity. The electric motor is received in the motorhousing and includes a stator, which is fixedly coupled to the motorhousing, and a rotor that is rotatable relative to the stator. The rotorincludes a motor output shaft. The transmission is at least partlydisposed in the gearbox cavity and includes a transmission input gear,which is coupled to the motor output shaft for rotation therewith, and atransmission output gear that is rotatable about an output axis. Thedifferential assembly is disposed in the gearbox cavity and includes adifferential input member, which is coupled to the transmission outputgear for rotation therewith about the output axis, and a pair ofdifferential output members. The differential bearing is receivedbetween the gearbox cover and the differential input member and supportsthe differential input member for rotation about the output axisrelative to the gearbox cover. The differential bearing cover has aflange, which is mounted to an exterior side of the gearbox cover, and apiloting portion having an annular shape and being fixedly coupled tothe flange. The spacer is disposed along the output axis between anouter bearing race of the differential bearing and an axial end of thepiloting portion that is opposite the flange. The output shaft isreceived through the piloting portion and the spacer and is drivinglycoupled to one of the differential output members.

In yet another form, the present disclosure provides an electric driveunit that includes a housing assembly, an electric motor, atransmission, a pair of first intermediate gear bearings, a pair ofretaining rings and a bearing cover. The housing assembly has a housingmember with an external surface. A pair of shaft bores are formedthrough the external surface, and a pair of counterbores are formed inthe external surface. Each of the counterbores is concentric with acorresponding one of the shaft bores and forms an annular shoulder. Theelectric motor received in the housing assembly. The transmission isreceived in the housing member and includes a transmission input gear,which is driven by the electric motor, a transmission output gear, and aplurality of intermediate gears in a drive train between thetransmission input gear and the transmission output gear. The pluralityof intermediate gears include a pair of compound gears, each of whichhaving first and second intermediate gears that are fixedly coupled toan intermediate gear shaft. Each of the first intermediate gears ismeshingly engaged to the transmission input gear. Each of the firstintermediate gear bearings is received in a corresponding one of theshaft bores and supports an associated one of the intermediate gearshafts for rotation about a respective axis relative to the housingmember. Each of the first intermediate gear bearings has an outerbearing race. A retaining ring groove is formed into an outercircumferential surface of each of the outer bearing races. Each of theretaining rings is received in the retaining ring groove in acorresponding one of the outer bearing races and abuts a correspondingone of the shoulders. The bearing cover is mounted to the housing memberto close the counterbores. The bearing cover defines two sets of pads.Each set of pads is abutted against an axial end face of an associatedone of the intermediate gear bearings and is configured to limitmovement of the associated one of the intermediate gear bearings in adirection away from the housing member.

In still another form, the present disclosure provides an electric driveunit that includes a housing assembly, an electric motor, atransmission, a differential assembly, a differential bearing and atrough. The housing assembly has a motor housing, which defines a motorcavity, a gearbox and a gearbox cover. The gearbox is coupled to themotor housing, while the gearbox cover is coupled to the gearbox. Thegearbox and the gearbox cover cooperate to form a gearbox cavity. Aportion of the gearbox cavity is employed as a sump for holding a liquidlubricant. The electric motor is received in the motor housing andincludes a stator, which is fixedly coupled to the motor housing, and arotor that is rotatable relative to the stator. The rotor includes amotor output shaft. The transmission is at least partly disposed in thegearbox cavity and includes a transmission input gear, which is coupledto the motor output shaft for rotation therewith, and a transmissionoutput gear that is rotatable about an output axis. A portion of thetransmission output gear extends into the sump. The differentialassembly is disposed in the gearbox cavity and includes a differentialinput member, which is coupled to the transmission output gear forrotation therewith about the output axis, and a pair of differentialoutput members. The differential bearing is received between the gearboxcover and the differential input member. The differential bearingsupports the differential input member for rotation about the outputaxis relative to the gearbox cover. The trough is mounted to at leastone of the gearbox and the gearbox cover. The trough is received aboutthe portion of the transmission output gear that extends into the sump.

In another form, the present disclosure provides an electric drive unitthat includes an electric motor, a housing assembly and a seal member.The electric motor is received in the housing assembly and has a statorand a rotor. The stator includes a stator core and a plurality of fieldwindings. The stator core defines a plurality of stator cooling passagesthat extend longitudinally through the stator core. Each of the fieldwindings is associated with a corresponding phase of electrical power.The field windings has a protruding portion that extend from an axialend of the stator core. The protruding portion is encapsulated in aplastic material. The rotor is rotatable relative to the stator about amotor axis. The housing assembly has an annular wall member that definesa seal groove. The seal member is received in the seal groove and formsa seal between the annular wall member and the plastic encapsulation onthe protruding portion of the field windings. A liquid coolant iscirculated through the stator cooling channels. The seal member inhibitsingress of the liquid coolant between the stator and the rotor.

In another form, the present disclosure provides an electric drive unitthat includes a housing assembly, an electric motor, a transmission, anda first output shaft. The housing assembly has a motor housing and agearbox. The motor housing defines a stator bore that is disposedconcentrically about a motor axis. The stator bore is defined by aradius. The gearbox being coupled to the motor housing. The housingassembly defines an output shaft bore that extends through the gearboxand the motor housing along an output axis that is offset from andparallel to the motor axis. The electric motor has a stator and a rotorthat is rotatable relative to the stator. The stator is received intothe stator bore and is engaged to the motor housing. The rotor includesa motor output shaft. The transmission is at least partly disposed inthe gearbox and includes a transmission input gear, which is coupled tothe motor output shaft for rotation therewith, and a transmission outputgear that is rotatable about the output axis. The first output shaft isdriven by the transmission and is disposed in the output shaft bore. Adistance between the motor axis and the output shaft bore is less thanthe radius of the stator bore.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a perspective view of an exemplary electric drive unitconstructed in accordance with the teachings of the present disclosure;

FIG. 2 is a longitudinal section view of the electric drive unit of FIG.1 taken along a rotational axis of an electric motor;

FIGS. 3 and 4 are elevation and perspective views, respectively, ofportions of the electric drive unit of FIG. 1 illustrating atransmission and a differential assembly in more detail;

FIG. 5 is a perspective view of a portion of the transmission,illustrating a compound gear in more detail;

FIG. 6 is a section view taken along the line 6-6 of FIG. 5 ;

FIGS. 7 and 8 are section views of portions of the electric drive unitof FIG. 1 , illustrating the compound gear mounted in a housingassembly;

FIG. 9 is a perspective view of a portion of the electric drive unit ofFIG. 1 , illustrating an internal side of an end cover;

FIGS. 10 and 11 are perspective section views of portions of theelectric drive unit of FIG. 1 illustrating the differential assembly asit is supported in the housing assembly;

FIG. 12 is a perspective view of a portion of the electric drive unit ofFIG. 1 illustration a portion of a housing assembly in more detail;

FIG. 13 is a rear perspective view of a differential bearing cover thatis shown in the portion of the housing assembly illustrated in FIG. 12 ;

FIGS. 14 and 15 are front and rear perspective views, respectively, of agearbox cover that is shown in the portion of the housing assemblyillustrated in FIG. 12 ;

FIG. 16 is a front perspective view of a gearbox that is shown in theportion of the housing assembly illustrated in FIG. 12 ;

FIG. 17 is a section view of a portion of the gearbox illustrating apump mount in more detail;

FIG. 18 is a perspective view of a portion of the electric drive unit ofFIG. 1 illustrating a coolant pipe as coupled to a coolant pipe aperturein the gearbox and extending into the rotor of the electric motor;

FIG. 19 is a section view of a portion of the electric drive unit ofFIG. 1 , illustrating the connection between the coolant pipe and thegearbox;

FIG. 20 is a perspective, partially sectioned view of a portion of theelectric drive unit of FIG. 1 illustrating the connection between thecoolant pipe and the rotor;

FIG. 21 is a perspective section view of a portion of the electric driveunit of FIG. 1 illustrating a trough that is mounted to the housingassembly to shield a transmission output gear from a liquid lubricantheld in a sump;

FIG. 22 is a perspective view of a portion of the electric drive unit ofFIG. 1 illustrating a motor housing cover and an end cover of thehousing assembly in more detail;

FIG. 23 is a view similar to that of FIG. 22 but with the end coverremoved to illustrate the motor housing cover in more detail;

FIG. 24 is a rear perspective view illustrating the motor housing coverand a bearing holder;

FIG. 25 is a section view taken through a portion of the electric driveunit of FIG. 1 and illustrating an inverter, the electric motor, themotor housing cover and the end cover in more detail;

FIG. 26 is an enlarged portion of FIG. 25 ;

FIGS. 27 and 28 are rear and front perspective views, respectively, thatillustrate the motor housing cover and the bearing holder in moredetail;

FIG. 29 is an enlarged portion of FIG. 25 ;

FIG. 30 is a perspective view of a portion of the electric drive unit ofFIG. 1 , illustrating a floating seal in more detail;

FIG. 31 is an enlarged portion of FIG. 25 ;

FIG. 32 is a perspective view of a portion of the electric drive unit ofFIG. 1 , illustrating a sensor mount in more detail;

FIG. 33 is a section view taken through the sensor mount of FIG. 32 ;

FIG. 34 is a longitudinal section view of the electric drive unit ofFIG. 1 , taken along a rotational axis of the rotor of the electricmotor;

FIG. 35 is a perspective view of a portion of the electric drive unit ofFIG. 1 illustrating a field capacitor cavity formed in the housingassembly;

FIG. 36 is a perspective view of a portion of the electric drive unit ofFIG. 1 illustrating a stator of the electric motor and an output shaft;

FIG. 37 is an elevation view of a portion of the electric drive unit ofFIG. 1 illustrating a control board, an output shaft and a motor housingof the housing assembly;

FIGS. 38 and 39 are perspective section views of portions of theelectric drive unit of FIG. 1 illustrating the motor housing and theoutput shaft;

FIG. 40 is a section view of a portion of the electric drive unit ofFIG. 1 , illustrating portions of the inverter and the electric motor inmore detail;

FIG. 41 is a perspective view of a portion of the electric motor,illustrating the stator in more detail;

FIG. 42 is a perspective view of a portion of the electric motor,illustrating a phase terminal in more detail;

FIG. 43 is an end view of a portion of the inverter, illustrating aninverter mount in more detail;

FIG. 44 is a bottom perspective view of the inverter mount;

FIG. 45 is a perspective view of a portion of the inverter, illustratinga heat-sinked power semiconductor in more detail;

FIG. 46 is a perspective view of a portion of the inverter, illustratingthe heat-sinked power semiconductors and a plurality of bus bars beingcoupled to the inverter mount;

FIG. 47 is a perspective view of a portion of the inverter, illustratinga positive busbar in more detail;

FIG. 48 is an enlarged portion of FIG. 47 ;

FIG. 49 is a perspective view of a portion of the inverter, illustratinga ground busbar in more detail;

FIG. 50 is a perspective view of a portion of the inverter, illustratinga phase busbar in more detail;

FIG. 51 is an enlarged portion of FIG. 50 ;

FIGS. 52 and 53 are perspective views of portions of the inverter thatillustrate the busbars and the heat-sinked power semiconductorsassembled to the inverter mount;

FIG. 54 is a perspective view illustrating the busbars as coupled to theheat-sinked power semiconductors;

FIG. 55 is a perspective view of a portion of the inverter, illustratingthe integration of a current sensor with a phase busbar;

FIG. 56 is a perspective view of a sensor that is employed in thecurrent sensor shown in FIG. 55 ;

FIG. 57 is a perspective view of a portion of the electric drive unit ofFIG. 1 , illustrating the stator and an annular oil diverter in moredetail;

FIG. 58 is a section view of a portion of the electric drive unit ofFIG. 1 , illustrating the electric motor in more detail;

FIG. 59 are section views of exemplary, commercially-availablenon-contact seals;

FIGS. 60 and 61 are section views of portions of another electric driveunit constructed in accordance with the teachings of the presentdisclosure, the views illustrating portions of an electric motor, aninverter and an annular field capacitor;

FIG. 62 is a perspective, partly sectioned view of a portion of theinverter that is shown in FIGS. 60 and 61 ;

FIG. 63 is a perspective view of another exemplary electric drive unitconstructed in accordance with the teachings of the present disclosure;

FIG. 64 is a longitudinal section view of the electric drive unit ofFIG. 63 taken along a motor axis;

FIG. 65 is an enlarged portion of FIG. 64 , showing a portion of aninverter of a motor control unit in more detail;

FIG. 66 is an exploded perspective view of a portion of the electricdrive unit of FIG. 63 , the view illustrating a portion of the inverterin more detail;

FIG. 67 is a perspective section view of a portion of the electric driveunit of FIG. 63 , the view illustrating a cap and phase terminals of anelectric motor;

FIG. 68 is an enlarged portion of FIG. 66 ;

FIG. 69 is a perspective view illustrating a portion of the inverter ofthe electric drive unit of FIG. 63 ;

FIG. 70 is an exploded perspective view illustrating a positive busbar,a ground busbar and a plurality of phase busbars of the inverter of theelectric drive unit of FIG. 63 ;

FIG. 71 is an exploded perspective view of one of the phase busbars thatis illustrated in FIG. 70 ;

FIG. 72 is a perspective view of the phase busbar of FIG. 71 ;

FIG. 73 is an exploded perspective view similar to that of FIG. 71 butdepicting an alternately configured phase busbar; and

FIG. 74 is a perspective view of the phase busbar of FIG. 73 .

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

The patent application file contains at least one drawing executed incolor. Copies of the patent application with color drawings will beprovided by the office upon request and payment of the necessary fee.

In FIGS. 1 and 2 , an exemplary electric drive unit constructed inaccordance with the teachings of the present disclosure is generallyindicated by reference numeral 10. Components, aspects, features andfunctions of the electric drive unit 10 that are not expressly describedherein or shown (partly or fully) in the accompanying drawings, could beconfigured or function in a manner that is similar to the components,aspects, features and/or functions of electric drive units that aredescribed in co-pending U.S. patent application Ser. No. 16/751,596filed Jan. 24, 2020, U.S. patent application Ser. No. 16/865,912 filedMay 4, 2020, U.S. patent application Ser. No. 17/128,288 filed Dec. 21,2020, International Patent Application No. PCT/US2020/029925 filed Apr.24, 2020, International Patent Application No. PCT/US2020/062541 filedNov. 30, 2020, and/or U.S. Provisional Patent Application No. 63/159,511filed Mar. 11, 2021, the disclosures of which are incorporated byreference as if fully set forth in detail herein. In brief, the electricdrive unit 10 includes a housing assembly 12, a motor assembly 14, atransmission 16, a differential assembly 18, a pair of output shafts 20,which are rotatable about an output axis 22, and a lubrication andcooling system 24.

The housing assembly 12 can define one or more cavities (notspecifically shown) in which the motor assembly 14, the transmission 16,the differential assembly 18, and the output shafts 20 can be at leastpartly housed. In the example shown, the housing assembly 12 includes agearbox cover 30, a gearbox 32, a motor housing 34, a motor housingcover 36 and an end cover 38. The gearbox cover 30 and the gearbox 32abut one another and form a cavity into which the transmission 16 andthe differential assembly 18 are received, while the gearbox 32, themotor housing 34 and the motor housing cover 36 abut one another to forma cavity into which the motor assembly 14 is received.

With specific reference to FIG. 2 , the motor assembly 14 comprises anelectric motor 40, and a motor control unit 42 that includes an inverter44. The electric motor 40 can be a multi-phase electric motor andincludes a stator 46 and a rotor 48 that is rotatable about a motoroutput axis 50. The stator has a stator core and a plurality of fieldwindings that are wound about the stator core. Each of the fieldwindings is associated with a corresponding phase of electrical power.The rotor 48 includes a motor output shaft 52.

With reference to FIGS. 2 and 3 , the transmission 16 can be configuredin any desired manner to transmit rotary power between the motor outputshaft 52 and a differential input member 60 of the differential assembly18. The transmission 16 could comprise one or more fixed reductions ofany desired type, or could be configured as a multi-speed transmissionhaving two or more alternately engagable reductions (and optionally oneor more fixed reductions). The fixed or multi-speed reductions could beconfigured in any desired manner to permit the rotational axis of themotor output shaft to be oriented relative to the output axis 22 in adesired manner (e.g., parallel and offset, coincident, transverse,perpendicular, skewed).

In the example illustrated in FIGS. 3 and 4 , the transmission 16 is asingle-speed, multi-stage transmission employing a plurality of helicalgears. The transmission 16 comprises a transmission input gear 62, whichis coupled for rotation with the motor output shaft 52, a pair ofcompound gears 64 and a transmission output gear 66. Each of thecompound gears 64 is rotatable about an axis 68 that is parallel to andoffset from the motor output axis 50 and can include a first reductiongear 70, which can be meshingly engaged to the transmission input gear62, and a second reduction gear 72 that is coupled to the firstreduction gear 70 for rotation therewith and meshingly engaged to thetransmission output gear 66.

With reference to FIGS. 5 and 6 , each of the compound gears 64 can beconfigured such that the second reduction gear 72 is integrally andunitarily formed with a shaft member 80 and the first reduction gear 70is rotationally coupled to the shaft member 80 in a desired manner, suchas by laser welding. It will be appreciated, however, that the shaftmember 80 could be integrally and unitarily formed with the firstreduction gear 70 or could be a discrete component to which both thefirst and second reduction gears 70 and 72 are rotationally coupled. Theshaft member 80 can extend axially outwardly from each of the first andsecond reduction gears 70 and 72. In the particular example provided,the shaft member 80 and the second reduction gear 72 are identicalcomponents in each of the compound gears 64. It will be appreciated,however, that the shaft member 80 and the second reduction gear 72 couldbe unique for each of the compound gears 64, or that the compound gears64 (i.e., the first and second reduction gears 70 and 72 and the shaftmember 80 in the example provided) could be identical.

Returning to FIGS. 3 and 4 , the first reduction gears 70 can bedisposed in counterphase with respect to one another. In this regard,one of the first reduction gears 70 can be positioned such that one ofits teeth is received between and centered between two adjacent teeth onthe transmission input gear 62, and one of the teeth of the transmissioninput gear 62 is disposed between two adjacent teeth on the other one ofthe first reduction gears 70. It will be appreciated, however, that theother phasing could be employed, and that the teeth of both of the firstreduction gears 70 could be in-phase with one another. The secondreduction gears 72 can be disposed in-phase with one another. In thisregard, one of the teeth on a first one of the second reduction gears 72is received and centered between a first pair of adjacent teeth on thetransmission output gear 66, while at the same time one of teeth on thesecond one of the second reduction gears 72 is received and centeredbetween a second pair of adjacent teeth on the transmission output gear66. It will be appreciated, however, that other phasing could beemployed, that the teeth of the second reduction gears 72 could be in acounter-phase orientation with one another, and that the phasing of thesecond reduction gears 72 can be the same or different from the phasingof the first reduction gears 70.

With reference to FIGS. 4, 7 and 8 , each compound gear 64 can besupported for rotation relative to the housing assembly 12 by a firstbearing 82 and a second bearing 84. In addition to the capability ofhandling and transmitting radially-directed forces between the compoundgear 64 and the housing assembly 12, the first bearing 82 can be a typeof ball bearing that is configured to handle and transmit forces thatare directed axially along the rotational axis 68 of the compound gear64 when rotary power is transmitted through the transmission 16. Forexample, the first bearing 82 could be a type of angular contact bearingor a deep groove ball bearing. The first bearing 82 can be received in abore 86 formed in the gearbox cover 30 and a snap ring 88 or other typeof engagement could be received into a counterbore, which is concentricwith the bore 86, and secured to the outer bearing race of the firstbearing 82. The snap ring 88 can abut a shoulder formed in an axial endof the counterbore in the gearbox cover 30 to inhibit axial movement ofthe first bearing 82 in a first axial direction along the rotationalaxis 68 of the compound gear 64. The housing assembly 12 can furthercomprise a bearing cover 90 that can be mounted to the gearbox cover 30to close the bores 86 in the gearbox cover 30 and shroud the firstbearings 82. If desired, pads or bosses 92 (FIG. 9 ) can be formed ontothe bearing cover 90 to radially overlap and axially abut the outerbearing races of the first bearings 82 to further support and stabilizethe first bearings 82. Additionally, or alternatively, passages 94 (FIG.9 ) can be provided in the bearing cover 90 to permit lubricationpassing through the first bearings 82 to drain to an oil drain channel96 in the gearbox cover 30 that permits the lubrication to drain to adesired area, such as a sump 98 (FIG. 2 ).

With reference to FIGS. 4 and 8 , the second bearing 84 can be a type ofbearing that is configured to at least substantially or exclusivelyhandle and transmit radially-directed forces between the compound gear64 and the housing assembly 12. Stated another way, the second bearing84 can be a type of bearing that has an insufficient ability to handleor transmit forces that are directed axially along the rotational axis68 of the compound gear 64 when rotary power is transmitted through thetransmission 16. In the example shown, the second bearing 84 is a rollerbearing that employs cylindrically-shaped rollers between an innerbearing race and an outer bearing race. The second bearing 84 can bereceived into a bore 99 formed into the gearcase 32. If desired, theinner bearing race could be formed onto the shaft member 80 to which thefirst and second reduction gears 70 and 72 are rotationally coupled.

With renewed reference to FIGS. 3 and 4 , the rotational axes 68 of thecompound gears 64 can be disposed relative to the motor output axis 50in any desired manner to satisfy or accommodate criteria such as theoverall speed or gear reduction of the transmission 16, the size of theenvelope into which the electric drive unit 10 (FIG. 1 ) can be packagedand/or the extent to which the loading of the teeth of the firstreduction gears 70 is equalized. In the example shown, the rotationalaxes 68 of the compound gears 64 and the motor output axis 50 aredisposed in a plane P and an even number of teeth are formed on thetransmission input gear 62. Configuration in this manner can help tobalance the loads that are transmitted between each of the firstreduction gears 70 and the transmission input gear 62.

With reference to FIGS. 10 and 11 , the differential assembly 18 canfurther include a pair of differential output members 100 and can employany desired means for permitting speed differentiation between thedifferential output members. In the example provided, the differentialinput member 60 is a differential case and the speed differentiationmeans comprises a differential gearset 102 in which the differentialoutput members 100 are bevel side gears. It will be appreciated,however, that the speed differentiation means could employ a differenttype of differential gearset (e.g., a planetary gear arrangement inwhich the gears of the planetary arrangement are formed as spur orhelical gears and one or more of the differential output members is asun gear or a planet carrier of the planetary arrangement, or a helicalgear arrangement in which the side gears are helical gears) or couldemploy one or more sets of clutches (e.g., friction clutches).

In FIGS. 10 and 12 , the housing assembly 12 is illustrated to include adifferential bearing cover 110 that is fixedly but removably coupled tothe gearbox cover 30. The differential bearing cover 110 defines anoutput shaft bore 112 that is disposed concentrically about the outputaxis 22. A bearing, such as a tapered roller bearing 114, can bedisposed on a trunnion 116 formed on the differential input member 60and an inner bearing race of the tapered roller bearing 114 can beabutted axially against a shoulder that is formed on the differentialinput member 60. An outer bearing race of the tapered roller bearing 114can be formed into a bearing bore 118 formed in the gearbox cover 30.The differential bearing cover 110 can include a piloting portion 120,which can be disposed in the bearing bore 118, and a flange 122 that canextend radially outwardly from the piloting portion 120. Threadedfasteners 124 can be disposed through the flange 122 and can be threadedinto holes formed in the gearbox cover 30. A suitable seal or gasket canbe disposed between the gearbox cover 30 and the differential bearingcover 110 to form a seal that inhibits the egress of lubrication fromthe housing assembly 12 through the joint that is formed by the gearboxcover 30 and the differential bearing cover 110. In the example shown,the seal comprises an O-ring 128 that is received over the pilotingportion 120 and abutted against the flange 122. The O-ring 128 is seatedbetween a chamfer that is formed about the bearing bore 118 and thedifferential bearing cover 110 and is configured to seal an annulargroove having a triangular cross-sectional shape that is defined by thechamfer, the outer diameter of the piloting portion 120 and an axial endof the flange 122. A shim 130 can be received axially between the outerbearing race of the tapered roller bearing 114 and the piloting portion120. The shim 130 can be “select fit” (i.e., specifically selected forits particular thickness from a set of shims having differentthicknesses) so as to aid in preloading the tapered roller bearing 114to a desired preload when the differential bearing cover 110 isinstalled to the gearbox cover 30. A shaft seal 134 can be received intothe output shaft bore 112. A corresponding one of the output shafts 20can be received through the output shaft bore 112 and through thetrunnion 116 on the differential input member 60 and can benon-rotatably coupled to a corresponding one of the differential outputmembers 100. In the example provided, the output shafts 20 have anexternally splined segment that matingly engages an internally splinedsegment formed onto the corresponding one of the differential outputmembers 100. One or more grooves 138 can be formed in the axial end 140of the piloting portion 120 to permit oil to drain through the pilotingportion 120 to an oil drain channel 146 in the gearbox cover 30 thatpermits the lubrication to drain to a desired area, such as a sump 98(FIG. 2 ).

FIGS. 14 and 15 illustrate the front and rear sides of the gearbox cover30 in more detail. A first cooling pipe bracket 150 can be fixedlycoupled to the inside surface of the gearbox cover 30. In the exampleprovided, the first cooling pipe bracket 150 is integrally and unitarilyformed with the gearbox cover 30.

FIG. 16 illustrates the front side of the gearbox 32 in more detail. Anstator oil return aperture 154 is formed through the gearbox 32 andpermits fluid exiting the stator 46 (FIG. 2 ) to return to the sump 98.A coolant pipe aperture 156 is formed through the gearbox 32 and isconfigured to transmit a flow of fluid therethrough that is adapted forcooling the rotor 48 (FIG. 2 ). A plurality of lubricant feed apertures160 can be formed into the gearbox 32 and can be configured to feed aflow of fluid into each of the bores 99 and a bore 158 that areconfigured to receive the second bearings 84 (FIG. 4 ), which supportthe compound gears 64 (FIG. 4 ), and a tapered roller bearing 114 a(FIG. 11 ) that supports the differential input member 60 (FIG. 11 ).The lubricant feed apertures 160 intersect various lubricant feedgalleries 162 that are formed through the gearbox 32. Second and thirdcoolant pipe brackets 164 and 166, respectively, are fixedly coupled tothe gearbox 32. In the example provided, the second and third coolantpipe brackets 164 and 166 are unitarily and integrally formed with thegearbox 32. A coolant pump intake port 168 is formed in the gearbox 32and fluidly couples the sump 98 to a pump bore 170 that is also formedin the gearbox 32 and which is configured to receive a pump (not shown)that is part of the lubrication and cooling system 24. An output shaftbore 172 is formed through the gearbox 32 and is configured to receive acorresponding one of the output shafts 20 (FIG. 2 ) therethrough.

In FIG. 17 , a portion of the gearbox 32 is shown in section view tobetter illustrate the pump bore 170 and one of the lubricant feedgalleries 162. The particular lubricant feed gallery 162 shown happensto intersect the pump bore 17. Accordingly, it will be appreciated thata pump can be mounted in the pump bore 170 and can discharge fluid tothe lubricant feed gallery 162 that intersects the pump bore 17.

In FIGS. 18 through 20 , a coolant pipe 200 is depicted connecting thecoolant pipe aperture 156 to a central passage 202 in the rotor 48. Thecoolant pipe 200 is configured to introduce a flow of a coolant fluidinto the rotor 48. The flow of coolant fluid is provided by the pumpthat is mounted to the gearbox 32 and is transmitted to the coolant pipeaperture 156 through various galleries (including gallery 206 in themotor housing 34) that are formed in the housing assembly 12. Clamps 208can fixedly secure the coolant pipe 200 to the second and third coolantpipe brackets 164 and 166 on the gearbox 32, while the first coolantpipe bracket 150 on the gearbox cover 30 can abut the coolant pipe 200on a side of the coolant pipe 200 that is opposite the rotor 48 toinhibit withdrawal of the coolant pipe 200 from the rotor 48. In theparticular example provided, the coolant pipe 200 extends into the rotor48 by a distance that equals or exceeds seven times the inside diameterof the coolant pipe 200. However, it will be appreciated that thedistance by which the coolant pipe 200 extends into the rotor 48 couldbe sized differently.

In FIG. 21 , a trough 220 is mounted to the gearcase cover 30 and thegearcase 32. The transmission output gear 66 rotates in the trough 220to reduce or eliminate the churning of fluid in the sump 98. The trough220 can be formed of a suitable plastic material and can include aplurality of posts 222 that are received (e.g., slip fit or press fit)into apertures formed in the gearcase cover 30 and the gearcase 32.

With reference to FIGS. 22 and 23 , the motor housing cover 36 defines acavity 230 for housing a rotational position sensor 232 and a portion ofa wire harness 234 that couples the rotational position sensor 232 to acontrol board (not shown) of the motor control unit 42 (FIG. 2 ). Themotor housing cover 36 can also define a fluid feed gallery 240, a fluiddrain gallery 242 and an output shaft bore 244. The motor housing cover36 is sealingly coupled to the motor housing 34 to fluidly couple aninlet 250 of the fluid feed gallery 240 to an outlet port 252 from aheat exchanger 254 of the lubrication and cooling system 24. The fluidfeed gallery 240 defines a plurality of gallery outlet ports 256 thatare configured to route fluid from the fluid feed gallery 240 into themotor control unit 42 (FIG. 2 ) and the electric motor 40 (FIG. 2 ) aswill be described in more detail below. The fluid drain gallery 242 canbe employed to route a lubricating and cooling fluid from a rotor shaftbearing (not shown) to a gallery (not shown) in the motor housing 34 toreturn the fluid to the sump 98 (FIG. 2 ). The output shaft bore 244 canbe sized to receive an output shaft seal 258 therein. A correspondingone of the output shafts 20 can extend through the motor housing cover36 and can be sealingly engaged to the output shaft seal 258. The endcover 38 can be sealingly coupled to the motor housing cover 36 to sealeach of the cavity 230, the fluid feed gallery 240, and the fluid draingallery 242.

In FIGS. 24 and 25 , the motor housing cover 36 can include a pilot rib260 that can be received into a bore 262 formed in the motor housing 34to aid in locating the motor housing cover 36 to the motor housing 34 ina desired manner. The pilot rib 262 can be shaped as a segment of acircle that is centered about the motor output axis 50. A bearing holder264 can be shown to be fixedly coupled (e.g., unitarily and integrallyformed with) the motor housing cover 36 and disposed concentricallyabout the gallery outlet ports 256 such that the gallery outlet ports256 pass axially through a portion of the bearing holder 264. Thebearing holder 264 can define a rotor shaft bore 270, a bearingcounterbore 272, sensor mount counterbore 274, a first external sealgroove 276, a second external seal groove 278 and a fluid distributiongroove 280. The rotor shaft bore 270 can be formed through the bearingholder 264 and can be sized to receive an end of the rotor 48 therein.The bearing counterbore 272 can be disposed in the distal end of thebearing holder 264, can be concentric with the rotor shaft bore 270, andis sized to receive a bearing 284 that is mounted on the rotor 48. Thebearing 284 is configured to support the end of the rotor 48 forrotation about the motor output axis 50 relative to the housing assembly12. The sensor mount counterbore 274 is formed the proximal end of thebearing holder 264, can be concentric with the rotor shaft bore 270, andintersects the cavity 230 in the motor housing cover 36. The sensormount counterbore 274 is sized to receive a sensor mount as will bediscussed in more detail below.

The first external seal groove 270 and the second external seal groove272 are spaced axially apart from one another along the motor outputaxis 50 and are each configured to receive a respective seal (notshown), such as an O-ring seal, therein. The seal in the first externalseal groove 270 is configured to form a fluid-tight seal between thebearing holder 264 and an inverter mount 290 of the inverter 44, whilethe seal in the second external seal groove 272 is configured to form afluid-tight seal between the bearing holder 264 and a cap 294 thatcovers the windings 296 of the stator 46. The fluid distribution groove280 is disposed along the motor output axis 50 between the first andsecond external seal grooves 270 and 272. The fluid distribution groove280 extends over a portion of the circumference of the bearing holder264 and intersects the gallery outlet ports 256. Accordingly, fluiddischarged from the fluid feed gallery 240 (FIG. 23 ) in the motorhousing cover 36 through the gallery outlet ports 256 passes into thefluid distribution groove 280 and is directed radially outwardly andcircumferentially about an interior perimeter of the inverter 44. Ifdesired, the downstream end of the fluid distribution groove 280 can beshaped in a manner that aids the outward progression of fluid toward theinverter 44. In the example provided, the downstream end of the fluiddistribution groove 280 is frustoconically shaped. Fluid passes througha plurality of heat sinks and power semiconductors (e.g., MOSFET's,IGBT's) in the inverter 44 to remove heat from the inverter 44. Fluiddischarged from the inverter 44 is routed against and around the cap 294that covers the windings 296 of the stator 46 before it is routed into aplurality of cooling channels 300 that are formed in a body 302 of thestator 46.

In FIG. 26 , a relatively small hole 310 is formed radially through thebearing holder 264 at a location that intersects or is somewhatdownstream from the fluid distribution groove 280. The hole 310intersects the bearing counterbore 272 and is configured to supply alubricating fluid to the bearing 284. A Belleville spring washer 312 canbe disposed between an internal shoulder on the bearing holder 264 thatdefines the proximal end of the bearing counterbore 272 and the bearing284. The Belville spring washer 312 acts as a spacer that is configuredto ensure that the flow of fluid exiting the hole 310 is not and doesnot become blocked by the outer bearing race of the bearing 284.

In FIGS. 27 through 29 , a well 320 and a drain gallery 322 are formedin the bearing holder 264. The well 320 intersects and extends radiallyoutwardly from the bearing counterbore 272. The well 320 extends in anaxial direction so as to be somewhat wider than the bearing 284. Thedrain gallery 322 connects the well 320 to the fluid drain gallery 242(FIG. 23 ) in the motor housing cover 36 (FIG. 23 ). Accordingly, fluidsupplied to the bearing 284 for its lubrication and/or cooling can bedischarged to the well 320 and will drain through the drain gallery 322to the fluid drain gallery 242 (FIG. 23 ) and then to the sump 98 (FIG.2 ).

In FIGS. 29 and 30 , a floating seal 330 is mounted to the motor outputshaft 52. The floating seal 330 is disposed radially between the motoroutput shaft 52 and the bearing holder 264, as well as axially on themotor output shaft 52 between a first shoulder and a second shoulder.The bearing 284 is abutted against the second shoulder. The floatingseal 330 has an annular body 332 and a circumferentially extending sealmember 334. The annular body 332 is sized to slip fit over the portionof the motor output shaft 58 that is disposed between the first andsecond shoulders. The annular body 332 can define a first set ofprojections 336, which face toward the first shoulder, and a second setof projections 338 that face toward the bearing 284. The first set ofprojections 336 can be spaced circumferentially apart from one anotherand can be configured to minimize the surface area over which theannular body 332 and the first shoulder are potentially able to contactone another. The second set of projections 338 can be spacedcircumferentially apart from one another and can be configured tominimize the surface area over which the annular body 332 and the outerbearing race of the bearing 284 are potentially able to contact oneanother. Additionally, the second set of projections 338 permitlubrication that has passed through the bearing 284 to drain through thesecond set of projections 338 into the well 320. The circumferentiallyextending seal member 334 can be sealingly engaged to the annular body332 and to the circumferentially extending surface of the bearingcounterbore 272.

In some instances, it may be possible to configure the bearing 284 as agreased bearing to eliminate the need for supplying fluid to anddraining fluid from the bearing 284 to thereby reduce the complexity ofvarious components, such as by omitting features, such as the hole 310(FIG. 26 ) in the bearing holder 264 (FIG. 26 ) and/or the fluid draingallery 242 (FIG. 23 ) in the motor housing cover 36 (FIG. 23 ), and/orthe well 320 (FIG. 27 ) and the drain gallery 322 (FIG. 27 ) in thebearing holder 264 (FIG. 27 ), and/or to eliminate various components,such as the floating seal 330. The (greased) bearing 284 could be asealed bearing, such as a bearing that uses non-contacting seals.Optionally, the bearing (not shown) that supports the opposite end ofthe rotor 48 (FIG. 2 ) could also be a greased bearing and can be asealed bearing (e.g., a bearing using non-contacting seals) oralternatively could be a bearing with a single seal in which the seal isa non-contacting seal and faces toward the rotor 48 (FIG. 2 ) while theopen or unsealed side of the bearing faces the transmission 16 (FIG. 2).

With reference to FIGS. 31 through 33 , the rotational position sensor232 can be disposed on a circuit board that can be mounted to a plug orsensor mount 350 that is fitted into the bearing holder 264. The sensormount 350 can have a body 352 and a plurality of fingers 354 that extendfrom and are resiliently (flexibly) coupled to the body 352. A recess358 can be formed in the body 352 on a side of the body 352 that isopposite the fingers 354. A seal groove 360 can be disposed about theperimeter of the body 352. A plurality of posts 362 can extend from anaxial end of the body 352 the side of the body 352 into which the recess358 is formed. The circuit board 232 cb of the rotational positionsensor 232 can be abutted to the axial end of the body 352 such that theposts 362 extend through holes (not specifically shown) in the circuitboard 232 cb and various components of the rotational position sensor232 are received into the recess 358. The posts 362 can be employed toheat-stake the circuit board 232 cb to the body 352 to thereby fixedlycouple the rotational position sensor 232 to the sensor mount 350. Thecircuit board 232 cb further includes a wire harness socket 232 whs thatis configured to receive a connector on the wire harness 234. A suitableseal 370, such as an O-ring, is received into the seal groove 360. Thesensor mount 350 is inserted into the interior of the bearing holder 264such that the seal 370 is sealingly engaged to the interior surface ofthe sensor mount counterbore 274 and the body 352 of the sensor mount350. If desired, a chamfer can be formed on the bearing holder 264 toaid in compressing the seal 370 when the sensor mount 350 is insertedinto the bearing holder 264. The body 352 of the sensor mount 350 canabut an internal shoulder that is formed on the bearing holder 264 wherethe rotor shaft bore 270 intersects the sensor mount counterbore 274.The fingers 354 frictionally engage the interior surface of the rotorshaft bore 270 to inhibit axial movement of the sensor mount 350 alongthe motor output axis 50. A suitable sensor target 376 can be mounted toan axial end of the motor output shaft 52. In the example provided, therotational position sensor 232 is a TMR sensor, and the sensor target376 is a diametrically poled magnet that is secured to the motor outputshaft 52 via a suitable adhesive. The wire harness 234 can be mounted tothe wire harness socket 232 whs to electrically couple the wire harness234 to the rotational position sensor 232.

With reference to FIGS. 34 and 35 , the motor control unit 42 includes afield capacitor 380 that is received into a capacitor cavity 382 that isformed in the motor housing 34. The capacitor cavity 382 is surroundedby a mounting flange 384 against which a cover 386 is secured to closethe open end of the capacitor cavity 382. The motor housing 34 includesa heat sink 388 that is configured to abut the field capacitor 380 whenthe field capacitor 380 is installed in the capacitor cavity 382. Ifdesired, the heat sink 388 could be unitarily and integrally formed withthe remainder of the motor housing 34, or could be a discrete componentthat is assembled to the remainder of the motor housing 34.Mass-reduction features, such as slots 390 can be formed into the heatsink 388 if desired. Threaded fasteners (not shown) can be employed tosecure the field capacitor 380 to the heat sink 388. If desired, athermally-conductive paste or foil can be disposed between the fieldcapacitor 380 and the heat sink 388.

In FIG. 36 , a stator bore 400 and an output shaft bore 402 are formedin the motor housing 34. The stator bore 400 is sized to receive thebody 302 of the stator 46 therein and the central or longitudinal axisof the stator bore 400 is the motor output axis 50. The output shaftbore 402 is sized to receive a corresponding one of the output shafts 20therein and the central or longitudinal axis of the output shaft bore402 is the output axis 22. In the example provided, the stator bore 400and the output shaft bore 402 are spaced apart from one another so thatthey do not intersect one another. If desired, however, the stator bore400 and the output shaft bore 402 could intersect one another to reducethe overall volume of the electric drive unit 10 (FIG. 1 ). Statedanother way, and assuming that the diameters of the stator bore 400 andthe output shaft bore 402 were the same as those in the exampleillustrated in FIG. 36 , the stator bore 400 could be configured tointersect the output shaft bore 402 such that the distance between themotor output axis 50 and the output axis 22 is smaller than thedimension D that is depicted in FIG. 36 (i.e., the distance D is smallerthan the radius of the stator bore 400).

With reference to FIGS. 37 through 39 , fluid that drain through thefluid drain gallery 234 (FIG. 23 ) in the motor housing cover 36 (FIG.23 ) is directed axially through the motor housing cover 36 (FIG. 23 )into a gallery 430 that is formed in the motor housing 34. The gallery430 intersects the output shaft bore 402. The output shaft bore 402 istapered, having a smaller diameter end proximate the axial end of themotor housing 34 that is adjacent the motor housing cover 36 (FIG. 2 ),and a larger diameter end proximate the axial end of the motor housing34 that is adjacent the gearbox 32. Configuration in this manner aidsthe draining of fluid through the output shaft bore 402 to the sump 98(FIG. 2 ), as well as ensures that sloshing fluid in the sump 98 (FIG. 2) cannot be pushed from the sump 98 (FIG. 2 ) to the rotor 48 (FIG. 2 )via the output shaft bore 402, the gallery 430 and the fluid draingallery 234 (FIG. 23 ).

With reference to FIG. 40 , the electrical connection between theelectric motor 40 and the inverter 44 is shown in more detail. Inaddition to the inverter mount 290, the inverter 44 comprises aplurality of power semiconductors 450, a plurality of busbars (e.g.,positive busbar 452, ground busbar 454, and a plurality of phase busbars456), and an inverter circuit board 458. The inverter 44 controls thefrequency of power supplied to the electric motor 40. More specifically,the inverter 44 employs the power semiconductors 450 (e.g., MOSFET's,IGBT's) to control the switching of DC electricity to create three ACelectric outputs, each being associated with a given phase of thewindings 296 of the stator 46. Each phase of the windings 296 is fixedlyand electrically coupled to a bridge member 594 on an associated one ofthe phase busbars 456 in the inverter 44.

With additional reference to FIGS. 41 and 42 , a phase terminal 470 iselectrically coupled to each phase of the windings 296. In the exampleprovided, an end (not shown) of the phase of the windings 296 isreceived into a winding aperture 472 in the phase terminal 470. In theexample shown, the winding aperture 472 is transverse to thelongitudinal axis of the phase terminal 470 and the end of the phase ofthe windings 296 is soldered to the phase terminal 470. The phaseterminal 470 can further include an anti-rotation feature, such asknurling 474, a seal groove 476 and a connecting feature 478. The sealgroove 476 can be configured to receive an associated seal, such as anO-ring, that can form a seal between the phase terminal 470 and theinverter mount 290. The connecting feature 478 aids in fixedly andelectrically coupling the phase terminal 470 to an associated one of thephase busbars 456. In the example provided, the connecting feature 478is a threaded aperture that is configured to receive a threaded fastener480 that is inserted through the bridge member 594 on an associated oneof the phase busbars 456 to thereby fixedly and electrically couple thephase terminal 470 to the bridge member 594.

The cap 294 can be formed by overmolding a material over the windings296. The material that is used to form the cap 294 is an electricallyinsulating material but also has relatively good thermally conductiveproperties. The phase terminals 470 are partly encased in the materialthat forms the cap 294. More specifically, the portion of the phaseterminals 470 that includes the winding aperture 472 and the knurling474 is encased in the material that forms the cap 294. The knurling 474and the material that forms the cap 294 cooperate to resist relativerotation between the phase terminal 470 and the cap 294.

With reference to FIGS. 43 and 44 , the inverter mount 290 isillustrated in more detail. The inverter mount 290 can include a base500, a plurality of terminal receptacles 502, a plurality of sensorreceptacles 504, a first side wall 506 and a second side wall 508. Thebase 500 can have a generally annular configuration. A first axial sideor face of the base 500 can have a central portion that is somewhatthicker than an outer portion that is disposed radially outwardly of thecentral portion. A second, opposite side or face of the base 500 can beflat. The base 500 can define a plurality of semiconductor mounts 510that can be formed into the central portion on the first face of thebase 500. Each of the semiconductor mounts 510 can define asemiconductor recess 512 and a plurality of semiconductor terminalapertures 514. The semiconductor mounts 510 can be disposed in anydesired arrangement, but in the particular example provided, thesemiconductor mounts 510 are disposed in a ring-shaped arrangement. Thesemiconductor terminal apertures 514 are disposed in each thesemiconductor recess 512 and are formed through the base 500. Each ofthe terminal receptacles 502 can have a first portion, which is locatedon the portion of the base 500 that is disposed radially outwardly ofthe central portion and which extend axially away from the first face ofthe base 500, and a second portion that extends axially away from thesecond face of the base 500. In the example shown, each of the terminalreceptacles 502 is a generally tubular structure that is disposedthrough the outer portion of the base 500. The terminal receptacles 502can be spaced circumferentially apart from one another. Each of thesensor receptacles 504 can extend from the second face of the base 500and can intersect an associated one of the terminal receptacles 502. Thefirst and second sidewalls 506 and 508 can be fixedly coupled to thebase 500 and can encircle the outer perimeter and the inner perimeter,respectfully, of the base 500. The first side wall 506 can extend fromthe first face of the base 500 by a relatively large distance and fromthe second face of the base 500 by a relatively short distance. Thesecond side wall 508 can extend from the second face of the base 500 bya relatively large distance and from the first face of the base by arelatively small distance. A seal groove 516 is formed about the firstside wall 506 and is configured to receive a seal 518 (FIG. 40 ) thereinthat sealingly engages the first side wall 506 and the motor housing 34(FIG. 40 . A seal that is mounted in the first external seal groove 276(FIG. 25 ) in the bearing holder 264 (FIG. 25 ) is sealingly engaged tothe bearing holder 264 (FIG. 25 ) and the radially inner surface of thesecond side wall 508.

In FIG. 45 , a heat sink 520 is illustrated as being fixedly coupled toone of the power semiconductors 450 to form a heat-sinked powersemiconductor assembly 522. The power semiconductor 450 includes aplurality of pins or terminals 524. The heat sink 520 can be formed of asuitable thermally conductive material and can be electrically coupledto an associated one of the terminals 524. As a non-limiting example,the heat sink 520 could be formed of a metal material, such as aluminum,brass, bronze or copper. The heat sink 520 can define a plurality offins 526 that can be employed to discharge heat into a flow of fluidpassing through the fins 526. In the particular example illustrated, thefins 526 comprise rod-like projections having an oval cross-sectionalshape, but it will be appreciated that the fins 526 can be formed in anydesired manner and can have any desired cross-sectional shape (e.g.,circular, rectangular, diamond). The heat sink 520 could be unitarilyand integrally formed, and if desired, the fins 526 can be formed withdraft (i.e., taper along their longitudinal axis). Alternatively, thefins 526 could be discrete components that are assembled/fixedly coupledto a base of the heat sink 520. Each of the heat sinks 520 can bedisposed between a pair of the power semiconductors 450 (i.e., each heatsink 520 is physically coupled to one of the power semiconductors 450and is adjacent, but circumferentially spaced from, another powersemiconductor 450). Each heat sink 520 can be configured such that theheight of the fins 526 (i.e., a distance that the fins 526 extend fromthe power semiconductor 450 of a given heat-sinked power semiconductorassembly 522) on a radially inward end of the heat sink 520 can beshorter than the height of the fins 526 on a radially outward end of theheat sink 520. Accordingly, the height of the heat sink 520 of aheat-sinked power semiconductor assembly 522 can taper between theradially inward end of the heat-sinked power semiconductor assembly 522and the radially outer end of the heat-sinked power semiconductorassembly 522.

With reference to FIGS. 43, 45 and 46 , each of the heat-sinked powersemiconductor assembly 522 can be mounted in a respective one of thesemiconductor mounts 510 on the inverter mount 290 such that each of thepower semiconductors 450 is received into a corresponding one of thesemiconductor recesses 512 and the terminals 524 on each of the powersemiconductors 450 are received through semiconductor terminal apertures514.

With reference to FIGS. 47 and 48 , the positive busbar 452 includes afirst busbar portion 550 and a second busbar portion 552 that arefixedly and electrically coupled to one another. The first and secondbusbar portions 550 and 552 can be generally similar in theirconstruction and as such, only the first busbar portion 550 will bedescribed in detail herein. The first busbar portion 550 can be formedof an electrically conductive material, such as copper, and can includean annular body 560, a conductor link 562 and a plurality of fingers564. The annular body 560 is sized to be received within the first sidewall 506 (FIG. 44 ) in the inverter mount 290 (FIG. 44 ). The innercircumference of the annular body 560 can be disposed radially outwardlyof the semiconductor terminal apertures 514 (FIG. 44 ). A plurality ofapertures 570 can be formed through the annular body 560 that permit theannular body 560 to be received over the terminal receptacles 502 (FIG.44 ) and the sensor receptacles 504 (FIG. 44 ). The conductor link 562can extend radially outwardly from the annular body 560 and can beconfigured to extend over the inverter mount 290 (FIG. 46 ) where it canbe disposed at a location where it can be electrically coupled to acapacitor (not shown). Each of the fingers 564 can having a firstportion 572 and a second portion 574. The first portion 572 can begenerally L-shaped, having a leg that extends radially inwardly from theinner circumferential edge of the annular body 560, and an arm thatextends away from the leg in a first circumferential direction. Thesecond portion 574 can extend from the distal end of the arm in adirection that is perpendicular to the annular body 560. It should benoted that the arms of the first portion 572 a of the fingers 564 of thesecond busbar portion 552 extends away from an associated one of thelegs in a second, opposite circumferential direction so that the arms ofthe first portions 572 and 572 a face one another. It will beappreciated that the fingers 564 are configured to electrically connectto a first set of the terminals 524 (FIG. 45 ) on a first set of thepower semiconductors 450 (FIG. 46 ).

The ground busbar 454 is illustrated in FIG. 49 and has a configurationthat is generally similar to that of the positive busbar 452 (FIG. 47 )except for the locations of the fingers 564′ and the radial length ofthe legs of the first portions 572′, 572 a′ of the fingers 564′. In thisregard, the fingers 564′ are configured to electrically connect to asecond set of the terminals 524 (FIG. 45 ) on a second set of the powersemiconductors 450 (FIG. 46 ).

With reference to FIGS. 50 and 51 , each phase busbar 456 can be formedin a manner that is similar to that of the positive busbar 452 (FIG. 47) except that the phase busbars 456 do not include a conductor link,each phase busbar 456 has first and second busbar portions 550″ and 552″that each have an annular segment-shaped body 560″, and the phasebusbars 456 each include sets of different fingers 564″, 564 a″, an endfinger 590, and a bridge 592. In the example provided, the fingers 564a″ are relatively longer than the fingers 564″, and the quantity of setsof the fingers 564″ is equal to the quantity of sets of fingers 564 a″on each of the phase busbars 456. The end finger 590 is configured toextend outwardly from the annular segment-shaped body 560″ of the phasebusbar 456. The bridge 592 has a bridge member 594 that is parallel tobut spaced apart from the first busbar portion 550″. A sensor slot 596is formed through one side of the bridge 592, while a fastener aperture598 is formed through the bridge member 594. The bridge 592 can befixedly coupled to the first busbar portion 550″ in any desired manner,such as projection welding.

With reference to FIGS. 40, 44, 45 and 52 , the positive busbar 452 canbe received within the first side wall 506 in the inverter mount 290such that the positive busbar 452 is abutted against the second side ofthe base 500 and each adjacent pair of the arms 574, 574 a (FIG. 48 ) isengaged to opposite sides of one of the terminals 524 on a respectiveone of the power semiconductors 450. A first electrically insulatingmember can be disposed over the positive busbar 452 and the groundbusbar 454 can be positioned within the first side wall 506 in theinverter mount 290 such that the ground busbar 454 is abutted againstthe first electrically insulating member and each adjacent pair of thearms of the fingers 564′ (FIG. 49 ) is engaged to opposite sides of oneof the terminals 524 on a respective one of the power semiconductors450. A second electrically insulating member can be disposed over theground busbar 454 and each of the phase busbars 456 can be positionedwithin the first side wall 506 and abutted against the second insulator.Each adjacent pair of the arms of the fingers 564″ and 564 a″ (FIG. 50 )of the phase busbar 456 is engaged to opposite sides of one of theterminals 524 on a respective one of the power semiconductors 450. Thepositive busbar 452, the ground busbar 454 and each of the phase busbars456 can be oriented relative to the inverter mount 290 such that theterminal receptacles 502 and an adjacent one of the sensor receptacles504 are received through each of the apertures 570. Each of theterminals can be soldered, sintered or welded to the set of fingers thatconnect the terminal to an associated one of the busbars to therebymechanically and electrically couple the terminals and busbars.

With reference to FIGS. 52 through 54 , it will be appreciated thatassembly of the several busbars to the power semiconductors in thismanner will position the distal ends of each of the fingers and endfingers in abutment with an associated one of the terminals 524 on anassociated one of the power semiconductors 450. Thereafter, the fingersand end fingers can be fixedly and electrically coupled to the terminals524, for example by resistance welding or resistance soldering adjacentpairs of them to the terminals 524.

In FIGS. 55 and 56 , the motor control unit 42 (FIG. 2 ) includes aplurality of current sensors 600, each of which being associated with acorresponding set of the terminal receptacles 502, the sensorreceptacles 504, and the bridges 592 on the phase busbars 456. Each ofthe current sensors comprises a sensor 602 and a plurality of C-shapedsensor laminations 604. The sensor 602 can be an eddy current sensor andcan be received in the sensor receptacle 504. The sensor laminations 604are abutted against one another and are received about the terminalreceptacle 502 between the first busbar portion 550″ and the bridgemember 594. The open ends of the sensor laminations 604 are disposed onopposite sides of the sensor receptacle 504 (i.e., a radially inner sideand a radially outer side).

With additional reference to FIG. 40 , the terminals 524 of the powersemiconductors 450 and the terminals of the sensor 602 are received intothe inverter circuit board 458 and can be electrically coupled to othercomponentry of the inverter circuit board 458 in a desired manner. Thephase terminals 470 are received into the terminal receptacles 502 andthe seal that is disposed in the seal groove 476 in each of the phaseterminals 470 forms a seal between the phase terminal 470 and theinverter mount 290 that inhibits the flow of fluid therethrough. Thethreaded fastener 480 is received through the fastener aperture 598 inthe bridge member 594 and is threadably engaged to the connectingfeature 478 to fixedly and electrically couple the phase terminal 470 tothe phase busbar 456.

During operation of the electric motor 40, current passing from thebridge member 594 of the phase busbar 456 to the phase terminal 470 willgenerate a magnetic field that will correspondingly generate eddycurrents in the sensor laminations 604. The sensor 602 is configured tosense the eddy currents in the sensor laminations 604 and responsivelygenerate a sensor signal that is indicative of a magnitude of eddycurrents in the sensor laminations. Significantly, the current sensor602 is positioned in as close a proximity to the interface between thephase busbar 456 and the phase terminal 470 as is possible.

FIGS. 57 and 58 depict a second cap 620 that is coupled to (e.g.,overmolded over) the windings 296 on an end of the motor 40 that extendsinto a cavity formed by the gearbox 32. The second cap 620 can begenerally similar to the cap 294 (FIG. 25 ). An annular oil diverter 622is mounted about the second cap 620 and aids in directing fluiddischarged from the cooling channels 300 (FIG. 25 ) to flow against theouter circumferential surface of the second cap 620 as well as an axialend of the second cap 620 that is spaced apart from the body 302 of thestator 46. A cylindrical projection 626 can be formed on the gearcase 32and can extend into the second cap 620. A seal 628, such as an O-ring,can be received into a groove formed in the cylindrical projection 626and can sealingly engage the inside circumferential surface of thesecond cap 620. A bore 630 can be formed through the axial end of thecylindrical projection 626 and can intersect a bearing bore 632 thathouses a bearing 634 that supports the motor output shaft 52. The bore630 can be sized to receive the motor output shaft 50 in anon-contacting manner. If desired, a non-contact seal, such as one ofthe non-contact seals shown in FIG. 59 , can be mounted in the bore 630to resist migration of fluid through the axial end of the cylindricalprojection 626.

With reference to FIGS. 60 through 63 , an alternately configuredinverter is shown. With reference to FIG. 60 , the field capacitor 380 bin this example is received in the motor housing 34 and has an annularconfiguration. The inverter 44 is received radially within the fieldcapacitor 380 b. If desired, the field windings 296 can be encapsulatedin an encapsulant material 700 that can form an annular chamber intowhich the field capacitor 380 b can be received. The encapsulantmaterial 700 can be cohesively bonded to the motor housing 34.Optionally, the encapsulant material 700 can be sealingly engaged with aseal member to form a seal between the encapsulant material and anothercomponent. For example, an O-ring 702 that is mounted to the motor cover36 b can form a seal between the motor cover 36 b and the encapsulantmaterial 700, while another O-ring 704, which is mounted to the bearingholder 264, can form a seal between the bearing holder 264 and an insidediametrical surface of an annular flange 706 that is formed by theencapsulant material 700.

With reference to FIGS. 61 and 62 , a cooling channel 710 is formed inthe motor cover 36 b and receives a flow of coolant/lubricant that isfed between a pair of seal members 702 and 712 that are mounted to themotor cover 36 b and engaged to the encapsulant material 700 and themotor housing 34, respectively. Fluid is discharged from the coolingchannel 710 into the fluid distribution groove 280 in the bearing holder264. It will be appreciated that the fluid in the fluid distributiongroove 280 can travel through the heat-sinked power semiconductorassemblies 522, about the field windings 296 and into the coolingchannels 300 in the stator 46.

With reference to FIGS. 63 and 64 of the drawings, another exemplaryelectric drive unit (EDU) constructed in accordance with the teachingsof the present disclosure is generally indicated by reference numeral1010. Except as described herein, the EDU 1010 can be configured in amanner that is similar to that of the electric drive unit that isillustrated and described in detail in U.S. Provisional PatentApplication No. 63/161,164 filed Mar. 15, 2021, the disclosure of whichis incorporated by reference as if fully set forth in detail herein. TheEDU 1010 includes a housing 1012 and a motor assembly 1014 that isreceived in the housing 1012 and which has an electric motor 1016 and amotor control unit 1018 that includes an inverter 1020. The electricmotor 1016 includes a rotor 1024, a motor output shaft 1026 and a stator1030. The rotor 1024 is rotatable relative to the stator 1030 about amotor axis 34. The motor output shaft 1026 is coupled to the rotor 1024for rotation therewith.

With reference to FIGS. 64 through 67 , the stator 1030 includes astator core 1040, a plurality of windings 1042, a plurality of phaseterminals 1044 and a cap 1046. The windings 1042 are wound about thestator core 1040 and are segregated into several phases.

Each phase terminal 1044 is mechanically and electrically coupled to anassociated phase of the windings 1042. In the example provided, an end1048 of a phase of the windings 1042 is received into a winding aperture1052 in a respective one of the phase terminals 1044. In the exampleshown, the winding aperture 1052 is transverse to the longitudinal axisof the phase terminal 1044 and the end of the phase of the windings 1042is physically and electrically coupled (e.g., soldered) to the phaseterminal 1044. The phase terminal 1044 can further include ananti-rotation feature, such as knurling 1056, a seal groove 1058 and aconnecting feature 1060. The seal groove 1058 can be configured toreceive an associated seal, such as an O-ring 1062, that can form a sealbetween the phase terminal 1044 and the inverter 1020. The connectingfeature 1060 aids in fixedly and electrically coupling the phaseterminal 1044 to the inverter 1020. In the example provided, theconnecting feature 1060 is a threaded aperture that is configured toreceive a threaded fastener 1066.

The cap 1046 can be a discrete component that can be formed in asuitable process, such as injection molding, and can be fitted over thewindings 1042. The cap 1046 defines a plurality of pockets 1070, each ofwhich being disposed about a respective one of the phase terminals 1044.The material that is used to form the cap 1046 is an electricallyinsulating material but also has relatively good thermally conductiveproperties. A suitable material, such as an epoxy material 1072, can beinjected between the windings 1042 and the cap 1046 and can fill thepockets 1070 to a desired extent to seal between the interior surface ofeach of the pockets 1070 and an associated one of the phase terminals1044. It will be appreciated that the phase terminals 1044 are partlyencased in the epoxy material 1072. More specifically, the knurling 1056on each phase terminal 1044 is encased in the epoxy material 1072. Theknurling 1056 and the epoxy material 1072 cooperate to resist relativerotation between the phase terminal 1044 and the cap 1046.

With reference to FIGS. 65, 66 and 68 , a portion of the inverter 1020is shown in more detail. The inverter 1020 includes an inverter mount1080, a plurality of power semiconductors 1082, a plurality of busbars(e.g., positive busbar 1090, ground busbar 1092, and a plurality ofphase busbars 1094), a plurality of insulating layers (not specificallyshown), and an inverter circuit board 1096. The inverter 1020 controlsthe frequency of power supplied to the electric motor 1016. Morespecifically, the inverter 1020 employs the power semiconductors 1082,which can be MOSFET's or IGBT's, for example, to control the switchingof DC electricity to create three AC electric outputs, with each ACelectric output being associated with a given phase of the windings 1042of the stator 1030. Each phase of the windings 1042 is fixedly andelectrically coupled to a bridge member 1212 on an associated one of thephase busbars 1094 in the inverter 1020.

The inverter mount 1080 can include a base 1120, a plurality of terminalreceptacles 1122, a plurality of sensor receptacles 1124, a first sidewall 1126 and a second side wall 1128. The base 1120 can have agenerally annular configuration. A first axial side or face of the base1120 can have a radially outer portion that is somewhat thicker than acentral portion that is disposed radially inwardly of the radially outerportion. A second, opposite side or face of the base 1120 can be flat.The base 1120 can define a plurality of semiconductor mounts (notspecifically shown) that can be formed into the radially outer portionon the first face of the base 1120. Each of the semiconductor mounts candefine a plurality of semiconductor terminal apertures (not specificallyshown). The semiconductor mounts can be disposed in any desiredarrangement, but in the particular example provided, the semiconductormounts are disposed in a ring-shaped arrangement about the outerperimeter of the base 1120. Each of the terminal receptacles 1122defines an aperture, which is formed through the base 1120, and can havea first portion, which is located on the central portion of the base1120 and which extends axially away from the first face of the base1120, and a second portion that extends axially away from the secondface of the base 1120. In the example shown, each of the terminalreceptacles 1122 is a generally tubular structure that is disposed onthe central portion of the base 1120. The terminal receptacles 1122 canbe spaced circumferentially apart from one another. Each of the sensorreceptacles 1124 can extend from the second face of the base 1120 andcan be disposed about an associated one of the terminal receptacles1122. The first and second sidewalls 1126 and 1128 can be fixedlycoupled to the base 1120 and can encircle the outer perimeter and theinner perimeter, respectfully, of the base 1120. The first side wall1126 can extend from the first face of the base 1120 by a first distanceand from the second face of the base 1120 by a second, relativelyshorter distance. The second side wall 1128 can extend from the firstface of the base 1120 by a third distance that can be relatively largerthan the first distance. A first seal groove 1132 is formed about thefirst side wall 1126 and is configured to receive a first seal 1134therein that sealingly engages the first side wall 1126 and the housing1012. A second seal groove 1136 is formed about the second side wall1128 and is configured to receive a second seal 1138 therein thatsealingly engages the second side wall 1128 and the cap 1046.

With reference to FIG. 69 , each of the power semiconductors 1082 has aplurality of pins or terminals 1150 and is fixedly coupled to arespective heat sink 1152 to form a heat-sinked power semiconductorassembly 1154. The heat sink 1152 can be formed of a suitable thermallyconductive material and can be electrically coupled to an associated oneof the terminals 1150. As a non-limiting example, the heat sink 1152could be formed of a metal material, such as aluminum, brass, bronze orcopper. The heat sink 1152 can define a plurality of fins 1156 that canbe employed to discharge heat into a flow of fluid passing through thefins 1156. The fins 1156 are schematically illustrated in the particularexample provided.

Returning to FIGS. 66 and 68 , each of the heat-sinked powersemiconductor assemblies 1154 can be mounted in a respective one of thesemiconductor mounts on the inverter mount 1080 such that each of thepower semiconductors 1082 is received into a corresponding one of thepower semiconductor recesses and the terminals 1150 on each of the powersemiconductors 1082 are received through semiconductor terminalapertures in the inverter mount 1080. Configuration in the mannerillustrated positions the power semiconductors 1082 radially outwardlyof the windings 1042.

With reference to FIGS. 66, 68 and 70 , the busbars and the insulatinglayers are stacked to form a busbar assembly in which an insulatinglayer is disposed between the positive busbar 1090 and the ground busbar1092, and an insulating layer is disposed between the ground busbar 1092and the phase busbars 1094. The insulating layers are formed of anelectrically insulating material and electrically insulate axiallyadjacent busbars from one another.

Each of the positive and ground busbars 1090 and 1092 and each of thephase busbars 1094 includes a first busbar portion 1160 a, 1160 b and1160 c, respectively, and a second busbar portion 1162 a, 1162 b and1162 c, respectively, that are fixedly and electrically coupled to oneanother. Each of the second busbar portions 1162 a, 1162 b and 1162 ccan be generally similar in their construction to their associated firstbusbar portion 1160 a, 1160 b and 1162 c, respectively, and as such,only the first busbar portions 1160 a, 1160 b and 1160 c will bedescribed in detail herein. Each of the first busbar portions 1160 a,1160 b and 1160 c can be formed of an electrically conductive material,such as copper, and can include a body 1170 a, 1170 b and 1170 c,respectively, and a set of fingers 1174 a, 1174 b and 1174 c,respectively. The first busbar portions 1160 a and 1160 b of thepositive busbar 1090 and the ground busbar 1092 also include a conductorlink 1176 a and 1176 b, respectively.

The bodies 1170 a and 1170 b of the positive busbar 1090 and the groundbusbar 1092 can have an annular shape, while the body 1170 c of eachphase busbar 1094 can be shaped as an annular segment. The bodies 1170a, 1170 b and 1170 c are sized to be received over the second side wall1128 of the inverter mount 1080 and within the first side wall 1126 ofthe inverter mount 1080. The outer circumference of the annular bodies1170 a, 1170 b and 1170 c can be disposed radially inwardly of thesemiconductor terminal apertures in the inverter mount 1080.

The annular bodies 1170 a and 1170 b can define a central aperture 1180,a plurality of terminal apertures 1182 and a cooling standpipe aperture1184 that are formed through the annular body 1170. The terminalapertures 1182 can be received over the terminal receptacles 1122 (FIG.65 ) and the sensor receptacles 1124 (FIG. 65 ), while the coolingstandpipe aperture 1184 can be received over a cooling standpipe 1200that is integrally formed with the inverter mount 1080. The coolingstandpipe 1200 is configured to direct coolant through the invertermount 1080 to a coolant chamber 1202 (FIG. 65 ) that is disposed betweenthe inverter mount 1080 and the cap 1046. Heat from the powersemiconductor assemblies 1154 and the windings 1042 can be transmittedto the coolant in the coolant chamber 1202 (FIG. 65 ) to thereby coolthe inverter 1020 and the electric motor 1016 (FIG. 64 ). The conductorlinks 1176 a and 117 b can extend radially outwardly from the annularbody 1170 a and 1170 b and can be configured to extend over the invertermount 1080 and disposed at locations where they can be electricallycoupled to an associated terminal (not shown) of a capacitor (notshown). A bridge 1210 can be coupled to the radially inner side of thebody 1170 c of each of the phase busbars 1094. The bridge 1210 has abridge member 1212 that is parallel to but spaced apart from the body1170 c. A terminal aperture is formed through the bridge member 1212.The bridge 1210 can be fixedly coupled to the body 1170 c in any desiredmanner, but in the particular example provided the bridge 1210 isintegrally and unitarily formed with the body 1170 c.

Each of the sets of fingers 1174 a, 1174 b and 1174 c comprises aplurality of fingers that are configured to mechanically andelectrically couple a terminal 1150 (FIG. 69) of an associated one ofthe power semiconductors 1082 to an associated one of the positive,ground and phase busbars 1090, 1092 and 1094.

With reference to FIGS. 71 and 72 , each of the fingers (e.g., fingers1230) in a set of fingers (e.g., fingers 1174 c) can having a firstportion 1250, which can extend radially outwardly from the body (e.g.,body 1170 c), and at least one second portion 1252 that is configured tobe mechanically and electrically coupled to a respective terminal 1150(FIG. 69 ) on an associated one of the power semiconductors 1082 (FIG.69 ). In the example shown, each of first portions 1250 is disposed in aplane in which the body (e.g., body 1170 c) is disposed, each of thefirst portions 1250 is spaced circumferentially apart about the outsideperimeter of the body (e.g., body 1170 c), a pair of second portions1252 is coupled to each of the first portions 1250, and each of thesecond portions 1252 is generally L-shaped, having a leg 1254 thatextends from a respective one of the first portions 1250 and an arm 1256that extends from the leg 1254 in a direction that is perpendicular tothe leg 1254.

With reference to FIGS. 69 through 72 , the sets of fingers 1174 a, 1174b, 1174 c on the first portions 1160 a, 1160 b and 1160 c of thepositive, ground and phase busbars 90, 92 and 94 can be generallysimilar in their configuration. The relative length of the firstportions 1250 and the positioning of the second portions 1252 isconfigured so that each of the sets of fingers 1174 a, 1174 b and 1174 cis configured to engage a respective set of terminals on the powersemiconductors 1082. The set of fingers 1174 a of the first portion 1160a of the positive busbar 1090 are configured to be mechanically andelectrically coupled to a first one of the terminals 1150 on the powersemiconductors 1082, the set of fingers 1174 b of the first portion 1160b of the ground busbar 1092 are configured to be mechanically andelectrically coupled to a second one of the terminals 1150 on the powersemiconductors 1082, and the sets of fingers 1174 c of the first portion1160 c of the phase busbars 1094 are configured to be mechanically andelectrically coupled to a third one and a fourth one of the terminals1150 on the power semiconductors 1082. It will be appreciated that thesets of fingers 1174 a, 1174 b and 1174 c are staggered both in acircumferential direction and in a radial direction to avoid directelectrical coupling between two or more of the busbars.

Each of the second busbar portions 1162 a, 1162 b and 1162 c can begenerally similar to its associated first busbar portion 1160 a, 1160 band 1160 c, respectively, except for the configuration of the sets offingers 1174 a′, 1174 b′ and 1174 c′. More specifically, the fingers ofeach of the sets of fingers 1174 a′, 1174 b′ and 1174 c′ are offset fromthe fingers of the sets of fingers 1174 a, 1174 b and 1174 c in acircumferential direction and a second portion 1252′ of each of thefingers of the sets of fingers 1174 a′, 1174 b′ and 1174 c′ faces asecond portion 1252 of an associated one of the fingers of the sets offingers 1174 a, 1174 b and 1174 c. Construction in this manner permitseach terminal 1150 on each power semiconductor 1082 to be mechanicallyand electrically coupled to a second portion (e.g., second portion 1252)of a finger on a first busbar portion (e.g., first busbar portion 1160c) and to a second portion (e.g., second portion 1252′) on a finger on asecond busbar portion (e.g., second busbar portion 1162 c).

With reference to FIGS. 65, 66 and 68 , the positive busbar 1090 can bereceived within the first side wall 1126 in the inverter mount 1080 suchthat the positive busbar 1090 is abutted against the second side of thebase 1120 and each adjacent pair of fingers of the sets of fingers 1174a and 1174 a′ is engaged to a first one of the terminals 1150 on arespective one of the power semiconductors 1082. A first electricallyinsulating member can be disposed over the positive busbar 1090. Theground busbar 1092 can be received within the first side wall 1126 inthe inverter mount 1080 such that the ground busbar 1092 is abuttedagainst a side of the first electrically insulating member that isopposite the positive busbar 1090 and each adjacent pair of fingers ofthe sets of fingers 1174 b and 1174 b′ is engaged to a second one of theterminals 1150 on a respective one of the power semiconductors 1082. Asecond electrically insulating member can be disposed over the groundbusbar 1092. Each of the phase busbars 1094 can be positioned within thefirst side wall 1126 and abutted against the second insulator on a sideof the second insulator that is opposite the ground busbar 1092 and eachadjacent pair of fingers of the sets of fingers 1174 c and 1174 c′ isengaged to either third or fourth one of the terminals 1150 on arespective one of the power semiconductors 1082. The positive busbar1090, the ground busbar 1092 and each of the phase busbars 1094 can beoriented relative to the inverter mount 1080 such that the terminalreceptacles 1122 and an adjacent one of the sensor receptacles 1124 arereceived through each of the terminal apertures 1182 and the coolingstandpipe aperture 1184 is received over the cooling standpipe 1200.

It will be appreciated that assembly of the several busbars to the powersemiconductors in this manner will position the distal ends (i.e., arms1256 (FIG. 71 )) of each adjacent pair of the fingers in abutment withan associated one of the terminals 1150 on an associated one of thepower semiconductors 1082. Thereafter, the distal ends of the fingerscan be fixedly and electrically coupled to the terminals 1150, forexample by resistance welding or resistance soldering adjacent pairs ofthem to the terminals 1150.

In FIGS. 65 and 66 , the motor control unit 42 (FIG. 64 ) includes aplurality of current sensors 1300, each of which being associated with acorresponding set of the terminal receptacles 1122, the sensorreceptacles 1124, and the bridges 1210 on the phase busbars 1094. Eachof the current sensors 1300 comprises a sensor 1302 and a plurality ofC-shaped sensor laminations 1304. The sensor 1302 can be an eddy currentsensor and can be received in the sensor receptacle 1124. The sensorlaminations 1304 are abutted against one another and are received aboutan associated one of the terminal receptacles 1122 and axially betweenthe windings 1042 and the bridge member 1212 on an associated one of thephase busbars 1094. Accordingly, the open ends of the C-shaped sensorlaminations 1304 can straddle the portion of the sensor receptacle 1124where the sensor 1302 is located.

The terminals 1150 of the power semiconductors 1082 and the terminals ofthe sensor 1302 are received into the inverter circuit board 1096 andcan be electrically coupled to other componentry of the inverter circuitboard 1096 in a desired manner. The phase terminals 1044 are receivedinto the terminal receptacles 1122 and the seal 62 that is disposed inthe seal groove 1058 in each of the phase terminals 1044 forms a sealbetween the phase terminal 1044 and the inverter mount 1080 thatinhibits the flow of fluid therethrough. The threaded fastener 66 isreceived through the fastener aperture in the bridge member 1212 and isthreadably engaged to the connecting feature 1060 to fixedly andelectrically couple the phase terminal 1044 to the phase busbar 1094.

During operation of the electric motor 40 (FIG. 64 ), current passingfrom the bridge member 1212 of the phase busbar 1094 to the phaseterminal 1044 will generate a magnetic field that will correspondinglygenerate eddy currents in the sensor laminations 1304. The sensor 1302is configured to sense the eddy currents in the sensor laminations 1304and responsively generate a sensor signal that is indicative of amagnitude of eddy currents in the sensor laminations. Significantly, thecurrent sensor 1302 is positioned in as close a proximity to theinterface between the phase busbar 1094 and the phase terminal 1044 asis possible. When configured in this manner, the phase terminals 1044are disposed radially inwardly of the positive and ground busbars 1090and 1092, and the current sensors 1300 are disposed radially inwardly ofthe power semiconductors 1082.

While the inverter 1020 has been illustrated and described as includingpower semiconductors 1082 that are disposed about an outer perimeter ofthe several busbars, it will be appreciated that the teachings of thepresent disclosure have application to inverters that are configuredsomewhat differently, such as a configuration where the powersemiconductors are disposed about an inner perimeter of the severalbusbars. With reference to FIGS. 73 and 74 , an exemplary phase busbar1094 a is illustrated to include first and second busbar portions 1160c-1 and 1162 c-1, respectively, that each include sets of fingers 1174c-1 and 1174 c-1′, respectively that are disposed about an insideperimeter of the bodies 1170 c-1 and 1170 c-1′, respectively, of thefirst and second busbar portions 1160 c-1 and 1162 c-1.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. An electric drive unit comprising: a multi-phaseelectric motor having a stator and a rotor, the stator including astator core and a plurality of field windings, each of the fieldwindings being associated with a corresponding phase of electricalpower, the rotor being rotatable relative to the stator about a motoraxis; and an inverter having a plurality of power semiconductors, aninverter mount, and a plurality of busbars, each of the powersemiconductors having a plurality of terminals, the inverter mounthaving a base, the power semiconductors being mounted to the base of theinverter mount such that the terminals extend through the base and thepower semiconductors are arranged in an annular manner, each of thebusbars having a first busbar portion and a second busbar portion, thefirst busbar portion having a first body and a set of first fingers thatare fixedly coupled to the first body, the second busbar portion havinga second body and a set of second fingers that are fixedly coupled tothe second body, wherein each of the fingers in the set of first fingersand a corresponding one of the fingers in the set of second fingers ofeach of the busbars is mechanically and electrically coupled to oppositesides of a corresponding one of the terminals of the powersemiconductors; wherein the busbars comprise a positive busbar, a groundbusbar, and a plurality of phase busbars, each of the phase busbarsbeing mechanically and electrically coupled to an associated one of thefield windings.
 2. The electric drive unit of claim 1, wherein each ofthe terminals of the power semiconductors is welded to an associated oneof the first fingers and an associated one of the second fingers.
 3. Theelectric drive unit of claim 1, wherein each of the terminals of thepower semiconductors is soldered to an associated one of the firstfingers and an associated one of the second fingers.
 4. The electricdrive unit of claim 1, wherein each of the phase busbars has a bridgemember that is coupled to at least one of the first and second bodies,and wherein each of the windings includes a phase terminal that isfixedly coupled to the bridge member.
 5. The electric drive unit ofclaim 4, wherein a threaded fastener fixedly couples each phase terminalto an associated one of the bridge members.
 6. The electric drive unitof claim 4, wherein the inverter mount defines a plurality of terminalreceptacles, each of the phase terminals being received through acorresponding one of the terminal receptacles.
 7. The electric driveunit of claim 6, wherein the inverter mount defines a plurality ofsensor receptacles, wherein the inverter further includes a plurality ofcurrent sensors, each current sensor having a plurality of C-shapedlaminations and a sensor, the C-shaped laminations of each currentsensor being received about an associated one of the terminalreceptacles such that open ends of each of the C-shaped laminationsstraddle opposite sides of an associated one of the sensor receptacles,the sensor of each of the current sensors being received in acorresponding one of the sensor receptacles.
 8. The electric drive unitof claim 7, wherein the bridge member of each of the phase busbars isslotted to straddle a corresponding one of the sensor receptacles. 9.The electric drive unit of claim 1, wherein a heat sink is coupled toeach of the power semiconductors, wherein the heat sinks are disposed ina coolant chamber, and wherein the inverter mount defines a coolingstandpipe that is in fluid communication with the coolant chamber, thecooling standpipe being configured to permit a flow of coolant to passthrough the base of the inverter mount and circulate in a coolantchamber to cool the power semiconductors.
 10. The electric drive unit ofclaim 9, wherein each heat sink has a plurality of fins.
 11. Theelectric drive unit of claim 10, wherein each of the heat sinks isdisposed circumferentially between a pair of the power semiconductors.12. The electric drive unit of claim 11, wherein a height of the fins ona radially inward end of each heat sink is shorter than the height ofthe fins on a radially outward end of each heat sink.
 13. The electricdrive unit of claim 9, wherein each heat sink is electrically coupled toone of the terminals on a respective one of the power semiconductors.14. The electric drive unit of claim 1, wherein each finger in the setof first fingers has a first portion and at least one second portion,the first portion being fixedly coupled to and extending radiallyoutwardly from the first body, each of the at least one second portionbeing generally L-shaped having a first leg, which is coupled to andextends from the first portion, and a first arm that is coupled to thefirst leg on an end of the first leg that is opposite the first body,wherein each of the at least one second portion being spaced apart fromthe first body.
 15. The electric drive unit of claim 14, wherein thefirst portion of each of the fingers in the set of first fingers iscoplanar with the first body.
 16. The electric drive unit of claim 15,wherein each finger in the set of second fingers has a third portion andat least one fourth portion, the third portion being fixedly coupled toand extending radially outwardly from the second body, each of the atleast one fourth portion being generally L-shaped having a second leg,which is coupled to and extends from the third portion, and a second armthat is coupled to the second leg on an end of the second leg that isopposite the second body, wherein each of the at least one secondportion being spaced apart from the second body.
 17. The electric driveunit of claim 14, wherein the third portion of each of the fingers inthe set of second fingers is coplanar with the second body.
 18. Theelectric drive unit of claim 1, further comprising a transmission and atleast one output shaft, the transmission transmitting rotary powerbetween the rotor and the at least one output shaft.
 19. The electricdrive unit of claim 18, further comprising a differential assemblyhaving a differential input member and a differential gearset, thedifferential input member being driven by an output of the transmission,the differential gearset having a pair of differential output members,wherein the at least one output shaft comprises a pair of output shafts,and wherein each of the output shafts is drivingly coupled to anassociated one of the differential output members.
 20. The electricdrive unit of claim 1, wherein the inverter further comprises aplurality of insulating members, each of the insulating members beingdisposed between an associated axially-adjacent pair of the busbars. 21.The electric drive unit of claim 1, wherein the inverter furthercomprises a plurality of heat sinks, each of the heat sinks beingmechanically and electrically coupled to an associated one of the powersemiconductors to form a heat-sinked power semiconductor, wherein theheat-sinked power semiconductors are arranged such that the heat sink ofa first one of the heat-sinked power semiconductors is adjacent in acircumferential direction to the power semiconductor of an adjacentheat-sinked power semiconductor.
 22. The electric drive unit of claim21, wherein the heat-sinked power semiconductors are disposed radiallywithin the windings.
 23. The electric drive unit of claim 22, whereinthe inverter includes at least one capacitor that is electricallycoupled to the positive bus bar, the capacitor being disposed in anannular region about the windings.